http://www.sciencedaily.com/releases/2011/09/110901155301.htm"Half-matched bone marrow or stem cell transplants for blood cancer patients have typically been associated with disappointing clinical outcomes. However, a clinical trial conducted at the Kimmel Cancer Center at Jefferson testing its unique, two-step half-match procedure has produced some promising results: the probability of overall survival was 45 percent in all patients after three years and 75 percent in patients who were in remission at the time of the transplant.
...The patients received their transplant in two steps. First, after receiving radiation therapy to further treat their disease, the patients were given a specified dose of T cells (a type of immune cell that fights infection) from their half-matched family donor. The donors were parents, siblings or children of the patient. The patients next received the drug cyclophosphamide to help the newly infused donor T cells to be more tolerant to the patient's body. The second step of the transplant occurred when the patients received a dose of their donors' stem cells to help their blood counts return to normal and further strengthen their new immune system.
...Bone marrow or stem cell transplants are performed in order to replace a patient's diseased immune system with that of a healthy donor. Traditionally, the use of a genetically fully matched donor has been associated with the best results in bone marrow transplant, but many patients lack a fully-matched related or unrelated donor. Almost every patient will have a half-matched donor (also known as a haploidentical donor) in their family, however.
The successful use of haploidentical donors would greatly expand the number of donors available to a patient, extending this therapy to almost everyone who would benefit from receiving a transplant. This would include minority patients, including patients with sickle cell anemia, who do not have as many fully-matched unrelated donors available to them..."